Method of phase recovery in cellular communication systems
AssigneeMetawave Communications Corporation
InventorsPiu Bill Wong, Shimon B. Scherzer
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Abstract
This invention provides a CDMA (IS-95) cellular communication system, in which a base station transmits a common broadcast pilot signal through a sector wide beam and traffic signals through narrower adaptive spatial beams by way of an adaptive antenna array. The present invention further provides methods of recovering the phase mismatch between the pilot and traffic signals received at a mobile station, thereby providing for coherent demodulation. By implementing the phase-recovery process at individual mobile stations, the present invention enables the base station to transmit the traffic signals with optimal power gain and minimal interference.
Claims38
A method of cellular communication, comprising:
- a) transmitting a first cellular signal in a first beam, whereby said first cellular signal arrives at a receiver with a first phase;
- b) transmitting a second cellular signal in a second beam, whereby said second cellular signal arrives at said receiver with a second phase;
- c) recovering a phase mismatch between said first and second phases at said receiver;
- and
- d) utilizing said phase mismatch to demodulate at least one of said first and second cellular signals.
A cellular communication system employing a demodulation device, comprising:
- a) a means for constructing an in-phase signal from received first and second cellular signals, such that said in-phase signal is proportional to a cosine function of a phase mismatch between said first and second cellular signals;
- b) a means for constructing a quadrature-phase signal from said first and second cellular signals, such that said quadrature-phase signal is proportional to a sine function of said phase mismatch;
- c) a means for recovering said phase mismatch by way of said in-phase and quadrature-phase signals;
- and
- d) a means for producing an output signal from said in-phase and quadrature-phase signals, whereby said output signal is independent of said phase mismatch.
Dependencies are inferred from the claim text.